• Energy Research

The transition to clean energy is crucial for mitigating the impacts of climate change and achieving sustainable development. Reliance on fossil fuels, which are integral to manufacturing and transportation, remains a major contributor to greenhouse gas (GHG) emissions. Biomass gasification presents a renewable energy alternative that can significantly reduce emissions. However, proper disposal of municipal solid waste (MSW) and agricultural residues, such as date palm waste (DPW), is an increasing global challenge, including in Qatar. This study evaluates the economic feasibility of implementing an MSW and DPW gasification plant for clean electricity generation in Qatar. The country’s growing population and economic development have led to substantial waste production, making it an ideal location for waste-to-energy (WTE) initiatives. Using discounted cash flow (DCF) analysis, the study estimates the capital cost of a 373 MWth facility at approximately $12.07 million, with annual operating costs of about $4.09 million and revenue of $26.88 million in 2023. The results indicate a net present value (NPV) of $245.77 million, a return on investment (ROI) of 84.80%, a payback period of approximately 5 years over a 20-year project lifetime and a net reduction of 206,786 tonnes CO2 annually. These findings demonstrate the economic viability of biomass gasification in Qatar while contributing to reduced GHG emissions and advancing the country’s sustainability goals under Qatar National Vision 2030.

Abstract Livestock manures significantly contribute to greenhouse gas emissions and soil contamination if not valorised or disposed of properly. Meanwhile, hydrothermal liquefaction has emerged as a promising technology for the conversion of wet wastes into value-added products. As such, this study investigates the potential of hydrothermal liquefaction of camel manure and subsequent upgrading into drop-in fuels in Qatar. Experimental characterisation of manure samples is conducted, while a small-scale plant is simulated and evaluated using Aspen Plus®. Excess treated wastewater of Qatar is utilised as an alternative to fresh water in the process, while power is completely generated on-site. The demonstrated results are promising; whereby, a biocrude yield of 37.9% (on dry and ash-free basis) is achieved, while the biocrude is upgraded into a high-quality bio-gasoline. The produced bio-gasoline contributes to a 7% reduction in greenhouse gas emissions relative to conventional gasoline. The project capital investment is estimated to be 38 M$, while the bio-gasoline's minimum selling price is at 0.87 $/kg, which is still above the market price of conventional gasoline in Qatar (∼0.6 $/kg). However, the conducted sensitivity analysis indicates that scaling-up the plant by 5-fold can shift the fuel's minimum selling price below the average market price. As such, it has a high potential to be locally commercialised especially at times of petroleum price hikes.

Abstract The growing anthropogenic greenhouse gas (GHG) emissions combined with the rise of the demand on energy resources has expedited research into sustainable alternatives to fossil fuel. In this context, biomass has increased in popularity and acquired a significant share of the global energy mix in a relatively short time. However, several biomass resources have triggered wide criticism for compromising food resources, agricultural lands and fresh water to produce energy crops. Therefore, a second generation of non-edible biomass such as Jatropha curcas has become a major biofuel feedstock for several countries. Not only can its oil be converted into liquid fuels, but also the Jatropha fruit residues have high calorific value and are processed into several forms of energy. Several studies have investigated the different processing technologies to produce energy and food-related products, although no conclusions have been made on the most sustainable pathway for Jatropha utilisation considering its interlinkages to the energy, water and food resources, whilst considering its possible contributions to mitigating carbon emissions and the development of circular economies. As such, this study investigates 11 processing pathways for the major three components of Jatropha fruit from cradle to gate via a combination of three key tools including Energy-Water-Food (EWF) Nexus, Global Warming Potential (GWP) and Return on Investment (ROI). Aspen Plus software is used to simulate the production processes including transesterification, hydrotreatment, hydrocracking, gasification, pyrolysis, hydrothermal liquefaction, anaerobic digestion, saccharification and fermentation, incineration and detoxification. In addition, a mathematical model is developed to run a five-objective optimisation study using MATLAB. The model identifies an opportunity to process the Jatropha oil by transesterification (49%), hydrotreatment (28%) and hydrocracking (23%). while it is suggested that the seedcake is best utilised directly as fertilisers (35%) and processed for energy production by pyrolysis (30%) and anaerobic digestion (17%). Nevertheless, the shells of Jatropha are best utilised via SSF (32%), pyrolysis (28%), anaerobic digestion (22%) and incineration (11%).

Biochar from waste has emerged as a vital solution for multiple contemporary issues. While the organic content and porous structure of biochar have granted it multiple benefits. Where the use of biochar is proven to be beneficial for enhancing the soil structure and water and nutrients retention ability, therefore, saving water and boosting yields in arid regions. Moreover, biochar is capable to sequester carbon from the atmosphere and permanently store it within the soil. As such, this study evaluates the potential for carbon sequestration through biochar obtained from the pyrolysis of feedstock mixtures including camel manure, date pits, high-density polyethylene (HDPE) and low-density polyethylene (LDPE), and how it can enhance water and food security. Multiple energy and water supplying sources have been considered for different project scenarios to provide a broader understanding of biochar potentials. The lifecycle analysis (LCA) approach is utilized for the assessment of net emissions, while an economic study is conducted in Aspen Process Economic Analyser (APEA) to evaluate the feasibility of the different scenarios. Finally, single-objective optimization and multi-objective optimizations were carried out using excel and MATLAB genetic algorithm respectively to select optimal biomass blending and utilities options to fulfill the low cost and negative emissions targets. The assessment conducted for a Qatar case study indicates that the best waste blending scenario for maximum carbon sequestration potential was obtained at a mixing ratio of 20.4% Camel manure: 27% date pits: 26.3% LDPE: 26.4% HDPE. Furthermore, the optimum char blend for maximum carbon sequestration corresponding to the minimum cost of char mix was computed. The optimal biochar mixing percentage for highest net emission was obtained at a feedstock mixing ratio of 96.8% of date pits, 1.5% of LDPE, and 1.7% of HDPE with 0% of camel manure with an optimal cost of 313.55 $/kg biochar. Solar PV was selected as the best energy source in this pyrolysis study due to its reduced carbon emissions in comparison to other sources studied such as natural gas, coal and diesel. However, natural gas is selected to fulfill the economic objective. Moreover, the optimal water source was investigated including wastewater treatment, multi-stage flash and reverse osmosis desalination, where treated wastewater is selected as the optimal supply to fulfill both, economic and environmental objectives.

Investing in Sustainable Aviation Fuel (SAF) is crucial for reducing the aviation industry’s carbon footprint and mitigating climate change. As global air travel demand increases, SAF offers a viable solution to significantly lower greenhouse gas emissions and enhance energy security, ensuring a more sustainable future for aviation. Additionally, converting biomass, particularly waste materials, into SAF adds value by turning potential environmental liabilities into valuable energy resources, promoting a circular economy and reducing overall waste. This study evaluates the aircraft performance of a novel sustainable aviation fuel (SAF) derived from multiple feedstocks in a hybrid biorefinery. SAF performance is compared to two conventional jet fuels, specifically a blend of 30% kerosene and 70% gasoline and JET-A1. The results demonstrated that the optimal SAF outperformed conventional fuels in terms of both thrust and range. Specifically, SAF exhibited a 17% increase in thrust and a 10% increase in range compared to conventional Jet A1 fuel. This novel fuel did not only mitigate CO2 emissions and achieve a cost reduction of 0.13 to 8.08%, but also exhibited superior aircraft performance. In addition, this fuel also meets the criteria of a “drop-in fuel” as it does not necessitate significant alterations to the currently existing CFM56-7B turbofan engine. This is due to its similar key thermodynamic indicators, such as heat capacities and combustion temperature, which are comparable to those of conventional jet fuels. In addition, this paper identifies the sensitivity of the CFM56–7B turbofan engine fuelled by the novel fuel.

Abstract In this study, an empirical model for the pyrolysis of major oil palm wastes (OPW) such as palm kernel shell (PKS), empty fruit bunches (EFB), and oil palm frond (OPF), and their blends is developed. Moreover, the techno-economic feasibility of the wastes is investigated to determine the type of waste that would be suitable for the commercialization of different types of products. According to the model results, the bio-oil dominates the pyrolysis process’ product output, accounting for 59.21, 50.51, 56.60, and 55.65% of PKS, EFB, OPF, and their blend, respectively. Whereas biochar yield is 23.21, 23.1, 22.95, and 23.08%, gas yield is 17.57, 26.38, 20.44, and 21.27%. The findings demonstrate that the feedstocks under consideration are mostly suitable for producing bio-oil. According to the economic analysis, PKS-based pyrolysis has the highest capital expenses (CAPEX), while EFB-based pyrolysis has the lowest CAPEX of all tested feedstocks. Furthermore, PKS has the highest operating expenses (OPEX) due to its relatively higher market price as well as higher moisture content, which necessitates more energy input during the drying stage. Among the feedstocks, OPF has delivered the highest profit of USD 17 M/year, with a 22% return on investment (ROI). In terms of investment capital payback period, all OPW feedstocks demonstrated a reasonable period of 4–6 years. Bio-oil is the most valuable pyrolysis product, with the highest market value when compared to biochar and syngas. The established prediction model can be utilized as a solid reference for biomass pyrolysis modelling studies. Furthermore, the predicted values are reasonable enough to be used in industrial process design.

Food waste has become a source of concern as it is generated abundantly worldwide and needs to be valorised into new products. In this study, cucumber, tomato, and carrot wastes were investigated as pyrolysis feedstocks as a single component (cucumber), a binary component mixture (cucumber and tomato), and a ternary component blend (cucumber, tomato, and carrot). Fourteen scenarios were simulated and evaluated based on varying the feedstock blend (single, binary, and tertiary), temperature (300 and 500 °C), and feedstock moisture content (5, 20, and 40%). Using an established empirical model, the effect of these parameters on product yields, techno-economic implications, energy requirements, and life cycle analysis (LCA) outcomes were investigated. The best performers of each scenario were determined, and their strengths and weaknesses were identified and compared with other scenarios. In terms of product yields, all three systems (single, binary, and tertiary) followed a similar pattern: bio-oil yields increased as temperature and feedstock moisture content increased, while biochar yields decreased as temperature and feedstock moisture content increased. The production of syngas, on the other hand, was only observed at elevated temperatures. The total energy requirement exhibited an increase with increasing temperature and feedstock moisture content. The economic evaluation revealed that the return on investment (ROI) value for the single component at 5% moisture content at 300 °C is 29%, with a payback period (PB) of only 3.4 years, which is potentially very appealing. The water footprint increased with increasing pyrolysis temperature but decreased with increasing moisture content in all scenarios. The land footprint is observed to remain constant despite changes in process conditions. The study's findings contribute to the pyrolysis process's scalability, technological advancement, and commercialisation.